Nonfogging container for moisture containing materials



' May 24, 1938.

L. L. M GRADY ET AL NONFOGGI NG CONTAINER FOR MOISTURE CONTAININGMATERIALS Filed 001;. 4, 1954 jmamama Patented May 24, 1933 mirth STATESPATENT orricr.

' NoNroGome comma FOR morsroan oom'smmomi'rnmats Leon L. McGrady,Rochester, N. Y., and Charles G. Rittenhcuse, Chicago. IlL, assignors,by

mesne assignments, to Eastman Kodak Company, Jersey City. N. 1., acorporation of New Jersey Application ombu- 4, 1934, Serial No. 14am ,4Claims. (o1. zoo-44).

This invention relates to the art of packaging,-

and, more particularly to a non-fogging type of carton for the packagingof moisture-containin materials, such as fruit, berries, .and other foodproducts, as well as numerous other articles of commerce.

As is well known, there is a growing. tendency among producers,especially producers of food- I stufl's, fruits, vegetables and thelike, to sell their products in package form rather than in bulk.

, This tendency has been the outgrowth, not only of a demand on the partof the public for more sanitary and attractive products, but also ofrecognition by the producers of the fact that packaged goods, generallyspeaking, keep better than when exposed in bulk; Regenerated celluloseand cellulose derivative thin sheeting has come greatly into vogue inthe packaging art as a result of this modern-trend and, 'so far aspreservation of the products themselves are concerned, has

terials commonly used in packaging possess drawbacks which prevent themfrom being universally accepted. For example, it has been found thatwhen moisture-containing materials, such as fruit, vegetables, berriesand the like, are scaled up or enclosed in containers consisting of, orcomprising, cellulosic material, such as regenerated cellulose orcellulose acetate, the moisture 30 evolved from the packaged goodscondenses and tainer. In. the case of regenerated cellulose the materialabsorbs the moisture and causes shrinkage or distortion which adverselyaffects the transparency of the material as well as producing anunsightly package. On the other hand, cellulose acetate and similartypes of cellulose derivative sheeting are much less subject toshrinkage and distortion, but due in to the fact that this type ofsheeting does notv absorb moisture to any considerable extent,condensation of themoisture takes place within the package, therebyfogging or sweating the inside surfaces of cellulose derivative materialby the ging action makes it impossible for the prospective purchaser toexamine the contents of the package without opening it and thusseriously affects its salability'. -As is well known, it is the clear,glistening transparency or cellulose derivative and regeneratedcellulose wrapping materials which give them their exceptional appeal tothe public and it is obvious that anything which adversely affects thistransparency, such as the con o5 densation of moisture or the distortionof the been highly successful. However, all of the maforms droplets onthe inside surfaces of the condeposition of minute droplets of water.This fog-' ,material, re'ndersit unsatisfactory for use in a largenumber of fields in which it could otherwise be satisfactorily employed.

It is, accordingly, one of the objects of the present invention toprovide a material which may be successfully employed in the manufactureof a non-fogging type of container for moisture-containing materials,especially such materials as fruit, vegetables, berries and the like.Another object is to provide a container for moisture-containingmaterials which is not susceptible to fogging or appreciable distortionfrom the effects ofmoisture. A further object is to provide acontaineryat least a portion of which consists of a cellulose derivativematerial, at least one side of which is provided with a coating whichwill prevent the accumulation of minute droplets of moisture in the formof I fog. A still further object is to provide a substantiallymoistureproof container composed of, or including, a cellulosederivative material sheet material moistureproofed on one sideandprovided with an ad- ,herent coating of special character on theother coating comprising an adherent substance possessing a high degreeof wetability and use of this material in the production of containers,either constituting the complete structure of the. container, or aportion thereof, as would be the case in the manufacture of theso-called window type of carton. D

In the following examples and description, we have set forth several ofthe preferred embodiments of our invention, but it is to beunderstoodthat they are included merely for purposes of illustration and not as alimitation thereof.

In the accompanying drawing,

Fig. 1 is a cross-section, on a greatly exaggerated scale, through asheet of cellulose derivative material having on one side a highlywetable coating. I

Fig. 2 is also an exaggerated cross-section through a sheet. ofmaterial-similar to the ma terial of Fig. 1, but also including amoistureproof coating in addition to the wetable coating.

Fig. 3 is a perspective view of a window carton in accordance with ourinvention.

Fig. 4 is a perspective view illustrating a slightly difierentembodiment of our invention.

As indicated abbve, we have discovered that the fogging or sweating ofcellulose derivative containers made from, or including, cellulosederivative material may be prevented by coating the inner surface of thematerial, that is the surface which is to be used-on the inside of theparent fllm thereon and which has a high *degree of wetability isconsidered as coming within the scope of our invention. It may bementioned in this connection that wetable material may be applieddirectly to the surface of the cellulose ester sheeting or the sheetingmay be provided with any of the customary substrate, such as subs ofcellulose nitrate or other cellulose esters.

According to one form of our invention, we may employ cellulose acetatesheeting as the material from which the container is to be made. Thissheeting may be, either a thin material of the order of .00088 to .015inch in thickness, or a thicker type, such as a sheeting running fromthe .003 to .02 inch in thickness, depending uponthe use to which it isto be put. If it is desired merely to provide a -window in a cartonformed of waxed cardboard, for example, the sheeting may be of one ofthe thinner types. If, however, the whole container is to be composed ofthe material, it should preferably be of one of the thicker types ofsheeting in order to withstand the mechanical strains to which it issubjected in use. In some cases the cellulose derivative material may becast in the form of a cylindrical or other type of container, providedwith ap propriate metallic or non-metallic end walls. The last two typesof containers are practically completely transparent.

Assuming that the sheet material is composed of cellulose acetate,it iscoated in accordance with our invention with one of the followingcompositions:

I. Gelatin 5 Glacial acetic acid c.c 50

' Water v 10 Methyl alcohols c.c 5 Acet c c 500 Percent by II. Casein1.0

onium hydromde (28%- aqueous solution) 2.0 Sodium hydromde 0.5Glycerine- 2.0 Water 24.5 Methyl alcohoi 50.0 Acetone- The solutionapplied in any convenient manner known to those skilled in the art, sucha by subbing, beading, spraying, or the ka Beach and J-.G. McNally N052,019,648. cases, the moistureproof coatingmay be applied ariaaeagardless of the particular method employed, there is deposited upon thesurface of the cellulose derivative sheet a thin film or coating ofadherent material oi high wetability.

Referring to Fig. 1 of the drawing, A rep resents the ba'se sheet ofcellulose acetate, while 3 represents the coating of highly wetable material deposited thereon. in Fig. 2 there is shown a slightly differentform of the material in which the base sheet A is provided on oneside-with the wetable coating B and on the opposite side. with amoistureproof coating 0. The moistureproof layer may be composed of amixture of gum and wax and applied to the sheeting in accordance withthe procedure set forth in the copending application of N. F. Beach,Serial No. Li91, "filed July 17, 1931. The moistureprooi coating may,however, comprise a layer of gum applied next to the sheeting, followedby a layer of wax in accordance with the procedure set forth in the U.S. patent to N. F. In some wetable layer.

In the manufacture of a carton in accordance with our invention, one mayfirst form the carton, as shown in Fig. 3, of waxed paper, cardboard,wood or similar material, P and provided with a cutout or window openingW.- An appropriately sized window S is cemented around the edges of thecutout portion W with an appropriate cement, thereby forming asubstantially moistureprooi package.

' in the form of our invention illustrated in Fig. 4, represents acellulose derivative container of cylindrical form which may befabricated from the cellulose derivative sheeting produced as describedabove, or'may be cast from a suitable cellulose derivative moldingcomposition and coated. on the inside with a thin layer of the adherentwetable material. The container K may be provided with appropriatemetallic or nonmetallicend closures E.

It is obvious that many changes in the specific method of carrying outour invention are possible and we are, accordingly, not limited to anyparticulariorm thereof, except by the appended i Many types of cellulosederivative sheeting may be employed in making containers in accordancewith the invention. For example, we may employ moisture'proofed orunmoi'stureprooied cellulose acetate, cellulose propi'onate. cellulosebutyrate, as well as certain of the mixed cellulose organic esters, suchas cellulose acetate propionate, cellulose acetate butyrate, celluloseacetatestearate, and others. We may even use cellulose nitrate sheeting,although it is not to be preferred due to its high degree ofinflammability and instability.

- As stated above, our inventionis particularly r cterlzed by the factthat containers or the window wrtions of window cartons made in accorncetherewith will. not log or sweat due to the detion oi droplets ofmoisture. This feamoisture within'a package, in the form of minutedroplets which appear to the eye as fog. This cannot take place with thematerial described herein due to the fact that the moisture forms acontinuous film over the surface of the wetable material, thuspreserving substantially perfect transparency of the original'sheeting.This same effect of course takes place regardless of whether thecellulose derivative materialis thick or thin,

all that is necessary being that it shall be coated on its inner surfacewith the adhesive film of wetable material.

' Our invention is also characterized by the fact that the materialdescribed herein is not subject to wrinkling or unsightly distortion dueto shrinkage or swelling, which is one of the most outstanding defectsof regenerated cellulose sheeting when used for packagingmoisture-containing materials.

It will readily be seen that when we employ a moistureproof type ofsheeting, in accordance with the invention, we are enabled to maintainthe moisturewithin -the package at a constant value, since the moisturecannot escape through the moistureproof sheeting. Notwithstanding thatthe moisture is retained within the package, as indicated above it doesnot give rise to fogging or unsightly distortion due to the presence ofthe wetable film thereon.

Our invention is of especial value in the packaging of fruits,vegetables, berries, and other food products containing in their naturalstate a considerable amount of moisture. It is now possible by the useof packages produced as described herein to package almost any type ofmoisturecontaining materials with highly satisfactory results. Thisopens up a large field which has, heretofore, been closed to themanufacturer of transparent cartons, and, likewise, has solved for theproducer of many types of grown and artificially manufactured foodproducts the problem of packing and shipping such products intransparent containers of the type which have been so widely successfulin other fields.

Having thus described our invention, what'we declare is new and desireto secure by Letters Patent of the United States is:

' gelatin.

1. A window-type carton adapted for packaging moisture containingmaterials without fogging of the window portion thereof, comprising sideand end walls at least one of-which has a window opening therein, apermanently transparent sheet of cellulose derivative material which isrelatively non-absorptive of moisture closing the window opening, saidsheet havin on its inner surface a thin, adherent, non-fogging coatingof solid, transparent, relatively moisture absorptive material.

.2. A window-type carton adapted for packaging moisturecontaining-materials without fogging of the windowportion.thereof/comprising side and end walls at least one of which hasa window opening therein, a permanently transparent sheet of cellulosederivative material which is relatively non-absorptive of moistureclosing the window opening, said sheet having on its inner surface athin, adherent, non-fogging coating of gingof the window portionthereof, comprising side and end walls at least one of which has awindow opening therein, a permanently transparent sheet of cellulosederivative material which is relatively non-absorptive of moistureclosing the window opening, said sheet having on its inner surface athin, adherent, non-fogging coating 01' solid, transparent, relativelymoisture absorptive material and having on its outer surface amoisture-proof coating.

LEON L. McGRAD CHARLES G. RI'I'IENHOUSE.

